1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "ble/le_device_db.h" 43 #include "ble/core.h" 44 #include "ble/sm.h" 45 #include "btstack_debug.h" 46 #include "btstack_event.h" 47 #include "btstack_linked_list.h" 48 #include "btstack_memory.h" 49 #include "gap.h" 50 #include "hci.h" 51 #include "l2cap.h" 52 53 #ifdef ENABLE_LE_SECURE_CONNECTIONS 54 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 55 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 56 #else 57 #define USE_MBEDTLS_FOR_ECDH 58 #endif 59 #endif 60 61 62 // Software ECDH implementation provided by mbedtls 63 #ifdef USE_MBEDTLS_FOR_ECDH 64 #include "mbedtls/config.h" 65 #include "mbedtls/platform.h" 66 #include "mbedtls/ecp.h" 67 #include "sm_mbedtls_allocator.h" 68 #endif 69 70 // 71 // SM internal types and globals 72 // 73 74 typedef enum { 75 DKG_W4_WORKING, 76 DKG_CALC_IRK, 77 DKG_W4_IRK, 78 DKG_CALC_DHK, 79 DKG_W4_DHK, 80 DKG_READY 81 } derived_key_generation_t; 82 83 typedef enum { 84 RAU_W4_WORKING, 85 RAU_IDLE, 86 RAU_GET_RANDOM, 87 RAU_W4_RANDOM, 88 RAU_GET_ENC, 89 RAU_W4_ENC, 90 RAU_SET_ADDRESS, 91 } random_address_update_t; 92 93 typedef enum { 94 CMAC_IDLE, 95 CMAC_CALC_SUBKEYS, 96 CMAC_W4_SUBKEYS, 97 CMAC_CALC_MI, 98 CMAC_W4_MI, 99 CMAC_CALC_MLAST, 100 CMAC_W4_MLAST 101 } cmac_state_t; 102 103 typedef enum { 104 JUST_WORKS, 105 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 106 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 107 OK_BOTH_INPUT, // Only input on both, both input PK 108 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 109 OOB // OOB available on both sides 110 } stk_generation_method_t; 111 112 typedef enum { 113 SM_USER_RESPONSE_IDLE, 114 SM_USER_RESPONSE_PENDING, 115 SM_USER_RESPONSE_CONFIRM, 116 SM_USER_RESPONSE_PASSKEY, 117 SM_USER_RESPONSE_DECLINE 118 } sm_user_response_t; 119 120 typedef enum { 121 SM_AES128_IDLE, 122 SM_AES128_ACTIVE 123 } sm_aes128_state_t; 124 125 typedef enum { 126 ADDRESS_RESOLUTION_IDLE, 127 ADDRESS_RESOLUTION_GENERAL, 128 ADDRESS_RESOLUTION_FOR_CONNECTION, 129 } address_resolution_mode_t; 130 131 typedef enum { 132 ADDRESS_RESOLUTION_SUCEEDED, 133 ADDRESS_RESOLUTION_FAILED, 134 } address_resolution_event_t; 135 136 typedef enum { 137 EC_KEY_GENERATION_IDLE, 138 EC_KEY_GENERATION_ACTIVE, 139 EC_KEY_GENERATION_DONE, 140 } ec_key_generation_state_t; 141 142 typedef enum { 143 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 144 } sm_state_var_t; 145 146 // 147 // GLOBAL DATA 148 // 149 150 static uint8_t test_use_fixed_local_csrk; 151 152 // configuration 153 static uint8_t sm_accepted_stk_generation_methods; 154 static uint8_t sm_max_encryption_key_size; 155 static uint8_t sm_min_encryption_key_size; 156 static uint8_t sm_auth_req = 0; 157 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 158 static uint8_t sm_slave_request_security; 159 #ifdef ENABLE_LE_SECURE_CONNECTIONS 160 static uint8_t sm_have_ec_keypair; 161 #endif 162 163 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 164 static sm_key_t sm_persistent_er; 165 static sm_key_t sm_persistent_ir; 166 167 // derived from sm_persistent_ir 168 static sm_key_t sm_persistent_dhk; 169 static sm_key_t sm_persistent_irk; 170 static uint8_t sm_persistent_irk_ready = 0; // used for testing 171 static derived_key_generation_t dkg_state; 172 173 // derived from sm_persistent_er 174 // .. 175 176 // random address update 177 static random_address_update_t rau_state; 178 static bd_addr_t sm_random_address; 179 180 // CMAC Calculation: General 181 static cmac_state_t sm_cmac_state; 182 static uint16_t sm_cmac_message_len; 183 static sm_key_t sm_cmac_k; 184 static sm_key_t sm_cmac_x; 185 static sm_key_t sm_cmac_m_last; 186 static uint8_t sm_cmac_block_current; 187 static uint8_t sm_cmac_block_count; 188 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 189 static void (*sm_cmac_done_handler)(uint8_t * hash); 190 191 // CMAC for ATT Signed Writes 192 static uint8_t sm_cmac_header[3]; 193 static const uint8_t * sm_cmac_message; 194 static uint8_t sm_cmac_sign_counter[4]; 195 196 // CMAC for Secure Connection functions 197 #ifdef ENABLE_LE_SECURE_CONNECTIONS 198 static sm_connection_t * sm_cmac_connection; 199 static uint8_t sm_cmac_sc_buffer[80]; 200 #endif 201 202 // resolvable private address lookup / CSRK calculation 203 static int sm_address_resolution_test; 204 static int sm_address_resolution_ah_calculation_active; 205 static uint8_t sm_address_resolution_addr_type; 206 static bd_addr_t sm_address_resolution_address; 207 static void * sm_address_resolution_context; 208 static address_resolution_mode_t sm_address_resolution_mode; 209 static btstack_linked_list_t sm_address_resolution_general_queue; 210 211 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 212 static sm_aes128_state_t sm_aes128_state; 213 static void * sm_aes128_context; 214 215 // random engine. store context (ususally sm_connection_t) 216 static void * sm_random_context; 217 218 // to receive hci events 219 static btstack_packet_callback_registration_t hci_event_callback_registration; 220 221 /* to dispatch sm event */ 222 static btstack_linked_list_t sm_event_handlers; 223 224 225 // Software ECDH implementation provided by mbedtls 226 #ifdef USE_MBEDTLS_FOR_ECDH 227 // group is always valid 228 static mbedtls_ecp_group mbedtls_ec_group; 229 static ec_key_generation_state_t ec_key_generation_state; 230 static uint8_t ec_qx[32]; 231 static uint8_t ec_qy[32]; 232 static uint8_t ec_d[32]; 233 #ifndef HAVE_MALLOC 234 // 4304 bytes with 73 allocations 235 #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 236 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 237 #endif 238 #endif 239 240 // 241 // Volume 3, Part H, Chapter 24 242 // "Security shall be initiated by the Security Manager in the device in the master role. 243 // The device in the slave role shall be the responding device." 244 // -> master := initiator, slave := responder 245 // 246 247 // data needed for security setup 248 typedef struct sm_setup_context { 249 250 btstack_timer_source_t sm_timeout; 251 252 // used in all phases 253 uint8_t sm_pairing_failed_reason; 254 255 // user response, (Phase 1 and/or 2) 256 uint8_t sm_user_response; 257 uint8_t sm_keypress_notification; 258 259 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 260 int sm_key_distribution_send_set; 261 int sm_key_distribution_received_set; 262 263 // Phase 2 (Pairing over SMP) 264 stk_generation_method_t sm_stk_generation_method; 265 sm_key_t sm_tk; 266 uint8_t sm_use_secure_connections; 267 268 sm_key_t sm_c1_t3_value; // c1 calculation 269 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 270 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 271 sm_key_t sm_local_random; 272 sm_key_t sm_local_confirm; 273 sm_key_t sm_peer_random; 274 sm_key_t sm_peer_confirm; 275 uint8_t sm_m_addr_type; // address and type can be removed 276 uint8_t sm_s_addr_type; // '' 277 bd_addr_t sm_m_address; // '' 278 bd_addr_t sm_s_address; // '' 279 sm_key_t sm_ltk; 280 281 uint8_t sm_state_vars; 282 #ifdef ENABLE_LE_SECURE_CONNECTIONS 283 uint8_t sm_peer_qx[32]; // also stores random for EC key generation during init 284 uint8_t sm_peer_qy[32]; // '' 285 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 286 sm_key_t sm_local_nonce; // might be combined with sm_local_random 287 sm_key_t sm_peer_dhkey_check; 288 sm_key_t sm_local_dhkey_check; 289 sm_key_t sm_ra; 290 sm_key_t sm_rb; 291 sm_key_t sm_t; // used for f5 and h6 292 sm_key_t sm_mackey; 293 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 294 #endif 295 296 // Phase 3 297 298 // key distribution, we generate 299 uint16_t sm_local_y; 300 uint16_t sm_local_div; 301 uint16_t sm_local_ediv; 302 uint8_t sm_local_rand[8]; 303 sm_key_t sm_local_ltk; 304 sm_key_t sm_local_csrk; 305 sm_key_t sm_local_irk; 306 // sm_local_address/addr_type not needed 307 308 // key distribution, received from peer 309 uint16_t sm_peer_y; 310 uint16_t sm_peer_div; 311 uint16_t sm_peer_ediv; 312 uint8_t sm_peer_rand[8]; 313 sm_key_t sm_peer_ltk; 314 sm_key_t sm_peer_irk; 315 sm_key_t sm_peer_csrk; 316 uint8_t sm_peer_addr_type; 317 bd_addr_t sm_peer_address; 318 319 } sm_setup_context_t; 320 321 // 322 static sm_setup_context_t the_setup; 323 static sm_setup_context_t * setup = &the_setup; 324 325 // active connection - the one for which the_setup is used for 326 static uint16_t sm_active_connection = 0; 327 328 // @returns 1 if oob data is available 329 // stores oob data in provided 16 byte buffer if not null 330 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 331 332 // horizontal: initiator capabilities 333 // vertial: responder capabilities 334 static const stk_generation_method_t stk_generation_method [5] [5] = { 335 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 336 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 337 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 338 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 339 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 340 }; 341 342 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 343 #ifdef ENABLE_LE_SECURE_CONNECTIONS 344 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 345 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 346 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 347 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 348 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 349 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 350 }; 351 #endif 352 353 static void sm_run(void); 354 static void sm_done_for_handle(hci_con_handle_t con_handle); 355 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 356 static inline int sm_calc_actual_encryption_key_size(int other); 357 static int sm_validate_stk_generation_method(void); 358 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 359 360 static void log_info_hex16(const char * name, uint16_t value){ 361 log_info("%-6s 0x%04x", name, value); 362 } 363 364 // @returns 1 if all bytes are 0 365 static int sm_is_null(uint8_t * data, int size){ 366 int i; 367 for (i=0; i < size ; i++){ 368 if (data[i]) return 0; 369 } 370 return 1; 371 } 372 373 static int sm_is_null_random(uint8_t random[8]){ 374 return sm_is_null(random, 8); 375 } 376 377 static int sm_is_null_key(uint8_t * key){ 378 return sm_is_null(key, 16); 379 } 380 381 // Key utils 382 static void sm_reset_tk(void){ 383 int i; 384 for (i=0;i<16;i++){ 385 setup->sm_tk[i] = 0; 386 } 387 } 388 389 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 390 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 391 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 392 int i; 393 for (i = max_encryption_size ; i < 16 ; i++){ 394 key[15-i] = 0; 395 } 396 } 397 398 // SMP Timeout implementation 399 400 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 401 // the Security Manager Timer shall be reset and started. 402 // 403 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 404 // 405 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 406 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 407 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 408 // established. 409 410 static void sm_timeout_handler(btstack_timer_source_t * timer){ 411 log_info("SM timeout"); 412 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 413 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 414 sm_done_for_handle(sm_conn->sm_handle); 415 416 // trigger handling of next ready connection 417 sm_run(); 418 } 419 static void sm_timeout_start(sm_connection_t * sm_conn){ 420 btstack_run_loop_remove_timer(&setup->sm_timeout); 421 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 422 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 423 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 424 btstack_run_loop_add_timer(&setup->sm_timeout); 425 } 426 static void sm_timeout_stop(void){ 427 btstack_run_loop_remove_timer(&setup->sm_timeout); 428 } 429 static void sm_timeout_reset(sm_connection_t * sm_conn){ 430 sm_timeout_stop(); 431 sm_timeout_start(sm_conn); 432 } 433 434 // end of sm timeout 435 436 // GAP Random Address updates 437 static gap_random_address_type_t gap_random_adress_type; 438 static btstack_timer_source_t gap_random_address_update_timer; 439 static uint32_t gap_random_adress_update_period; 440 441 static void gap_random_address_trigger(void){ 442 if (rau_state != RAU_IDLE) return; 443 log_info("gap_random_address_trigger"); 444 rau_state = RAU_GET_RANDOM; 445 sm_run(); 446 } 447 448 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 449 log_info("GAP Random Address Update due"); 450 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 451 btstack_run_loop_add_timer(&gap_random_address_update_timer); 452 gap_random_address_trigger(); 453 } 454 455 static void gap_random_address_update_start(void){ 456 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 457 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 458 btstack_run_loop_add_timer(&gap_random_address_update_timer); 459 } 460 461 static void gap_random_address_update_stop(void){ 462 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 463 } 464 465 466 static void sm_random_start(void * context){ 467 sm_random_context = context; 468 hci_send_cmd(&hci_le_rand); 469 } 470 471 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 472 // context is made availabe to aes128 result handler by this 473 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 474 sm_aes128_state = SM_AES128_ACTIVE; 475 sm_key_t key_flipped, plaintext_flipped; 476 reverse_128(key, key_flipped); 477 reverse_128(plaintext, plaintext_flipped); 478 sm_aes128_context = context; 479 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 480 } 481 482 // ah(k,r) helper 483 // r = padding || r 484 // r - 24 bit value 485 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 486 // r'= padding || r 487 memset(r_prime, 0, 16); 488 memcpy(&r_prime[13], r, 3); 489 } 490 491 // d1 helper 492 // d' = padding || r || d 493 // d,r - 16 bit values 494 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 495 // d'= padding || r || d 496 memset(d1_prime, 0, 16); 497 big_endian_store_16(d1_prime, 12, r); 498 big_endian_store_16(d1_prime, 14, d); 499 } 500 501 // dm helper 502 // r’ = padding || r 503 // r - 64 bit value 504 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 505 memset(r_prime, 0, 16); 506 memcpy(&r_prime[8], r, 8); 507 } 508 509 // calculate arguments for first AES128 operation in C1 function 510 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, sm_key_t t1){ 511 512 // p1 = pres || preq || rat’ || iat’ 513 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 514 // cant octet of pres becomes the most significant octet of p1. 515 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 516 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 517 // p1 is 0x05000800000302070710000001010001." 518 519 sm_key_t p1; 520 reverse_56(pres, &p1[0]); 521 reverse_56(preq, &p1[7]); 522 p1[14] = rat; 523 p1[15] = iat; 524 log_info_key("p1", p1); 525 log_info_key("r", r); 526 527 // t1 = r xor p1 528 int i; 529 for (i=0;i<16;i++){ 530 t1[i] = r[i] ^ p1[i]; 531 } 532 log_info_key("t1", t1); 533 } 534 535 // calculate arguments for second AES128 operation in C1 function 536 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 537 // p2 = padding || ia || ra 538 // "The least significant octet of ra becomes the least significant octet of p2 and 539 // the most significant octet of padding becomes the most significant octet of p2. 540 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 541 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 542 543 sm_key_t p2; 544 memset(p2, 0, 16); 545 memcpy(&p2[4], ia, 6); 546 memcpy(&p2[10], ra, 6); 547 log_info_key("p2", p2); 548 549 // c1 = e(k, t2_xor_p2) 550 int i; 551 for (i=0;i<16;i++){ 552 t3[i] = t2[i] ^ p2[i]; 553 } 554 log_info_key("t3", t3); 555 } 556 557 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 558 log_info_key("r1", r1); 559 log_info_key("r2", r2); 560 memcpy(&r_prime[8], &r2[8], 8); 561 memcpy(&r_prime[0], &r1[8], 8); 562 } 563 564 #ifdef ENABLE_LE_SECURE_CONNECTIONS 565 // Software implementations of crypto toolbox for LE Secure Connection 566 // TODO: replace with code to use AES Engine of HCI Controller 567 typedef uint8_t sm_key24_t[3]; 568 typedef uint8_t sm_key56_t[7]; 569 typedef uint8_t sm_key256_t[32]; 570 571 #if 0 572 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 573 uint32_t rk[RKLENGTH(KEYBITS)]; 574 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 575 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 576 } 577 578 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 579 memcpy(k1, k0, 16); 580 sm_shift_left_by_one_bit_inplace(16, k1); 581 if (k0[0] & 0x80){ 582 k1[15] ^= 0x87; 583 } 584 memcpy(k2, k1, 16); 585 sm_shift_left_by_one_bit_inplace(16, k2); 586 if (k1[0] & 0x80){ 587 k2[15] ^= 0x87; 588 } 589 } 590 591 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 592 sm_key_t k0, k1, k2, zero; 593 memset(zero, 0, 16); 594 595 aes128_calc_cyphertext(key, zero, k0); 596 calc_subkeys(k0, k1, k2); 597 598 int cmac_block_count = (cmac_message_len + 15) / 16; 599 600 // step 3: .. 601 if (cmac_block_count==0){ 602 cmac_block_count = 1; 603 } 604 605 // step 4: set m_last 606 sm_key_t cmac_m_last; 607 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 608 int i; 609 if (sm_cmac_last_block_complete){ 610 for (i=0;i<16;i++){ 611 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 612 } 613 } else { 614 int valid_octets_in_last_block = cmac_message_len & 0x0f; 615 for (i=0;i<16;i++){ 616 if (i < valid_octets_in_last_block){ 617 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 618 continue; 619 } 620 if (i == valid_octets_in_last_block){ 621 cmac_m_last[i] = 0x80 ^ k2[i]; 622 continue; 623 } 624 cmac_m_last[i] = k2[i]; 625 } 626 } 627 628 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 629 // LOG_KEY(cmac_m_last); 630 631 // Step 5 632 sm_key_t cmac_x; 633 memset(cmac_x, 0, 16); 634 635 // Step 6 636 sm_key_t sm_cmac_y; 637 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 638 for (i=0;i<16;i++){ 639 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 640 } 641 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 642 } 643 for (i=0;i<16;i++){ 644 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 645 } 646 647 // Step 7 648 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 649 } 650 #endif 651 #endif 652 653 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 654 event[0] = type; 655 event[1] = event_size - 2; 656 little_endian_store_16(event, 2, con_handle); 657 event[4] = addr_type; 658 reverse_bd_addr(address, &event[5]); 659 } 660 661 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 662 // dispatch to all event handlers 663 btstack_linked_list_iterator_t it; 664 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 665 while (btstack_linked_list_iterator_has_next(&it)){ 666 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 667 entry->callback(packet_type, 0, packet, size); 668 } 669 } 670 671 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 672 uint8_t event[11]; 673 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 674 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 675 } 676 677 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 678 uint8_t event[15]; 679 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 680 little_endian_store_32(event, 11, passkey); 681 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 682 } 683 684 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 685 uint8_t event[13]; 686 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 687 little_endian_store_16(event, 11, index); 688 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 689 } 690 691 static void sm_notify_client_authorization(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t result){ 692 693 uint8_t event[18]; 694 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 695 event[11] = result; 696 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 697 } 698 699 // decide on stk generation based on 700 // - pairing request 701 // - io capabilities 702 // - OOB data availability 703 static void sm_setup_tk(void){ 704 705 // default: just works 706 setup->sm_stk_generation_method = JUST_WORKS; 707 708 #ifdef ENABLE_LE_SECURE_CONNECTIONS 709 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 710 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 711 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 712 memset(setup->sm_ra, 0, 16); 713 memset(setup->sm_rb, 0, 16); 714 #else 715 setup->sm_use_secure_connections = 0; 716 #endif 717 718 // If both devices have not set the MITM option in the Authentication Requirements 719 // Flags, then the IO capabilities shall be ignored and the Just Works association 720 // model shall be used. 721 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 722 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 723 log_info("SM: MITM not required by both -> JUST WORKS"); 724 return; 725 } 726 727 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 728 729 // If both devices have out of band authentication data, then the Authentication 730 // Requirements Flags shall be ignored when selecting the pairing method and the 731 // Out of Band pairing method shall be used. 732 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 733 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 734 log_info("SM: have OOB data"); 735 log_info_key("OOB", setup->sm_tk); 736 setup->sm_stk_generation_method = OOB; 737 return; 738 } 739 740 // Reset TK as it has been setup in sm_init_setup 741 sm_reset_tk(); 742 743 // Also use just works if unknown io capabilites 744 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 745 return; 746 } 747 748 // Otherwise the IO capabilities of the devices shall be used to determine the 749 // pairing method as defined in Table 2.4. 750 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 751 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 752 753 #ifdef ENABLE_LE_SECURE_CONNECTIONS 754 // table not define by default 755 if (setup->sm_use_secure_connections){ 756 generation_method = stk_generation_method_with_secure_connection; 757 } 758 #endif 759 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 760 761 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 762 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 763 } 764 765 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 766 int flags = 0; 767 if (key_set & SM_KEYDIST_ENC_KEY){ 768 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 769 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 770 } 771 if (key_set & SM_KEYDIST_ID_KEY){ 772 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 773 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 774 } 775 if (key_set & SM_KEYDIST_SIGN){ 776 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 777 } 778 return flags; 779 } 780 781 static void sm_setup_key_distribution(uint8_t key_set){ 782 setup->sm_key_distribution_received_set = 0; 783 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 784 } 785 786 // CSRK Key Lookup 787 788 789 static int sm_address_resolution_idle(void){ 790 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 791 } 792 793 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 794 memcpy(sm_address_resolution_address, addr, 6); 795 sm_address_resolution_addr_type = addr_type; 796 sm_address_resolution_test = 0; 797 sm_address_resolution_mode = mode; 798 sm_address_resolution_context = context; 799 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 800 } 801 802 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 803 // check if already in list 804 btstack_linked_list_iterator_t it; 805 sm_lookup_entry_t * entry; 806 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 807 while(btstack_linked_list_iterator_has_next(&it)){ 808 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 809 if (entry->address_type != address_type) continue; 810 if (memcmp(entry->address, address, 6)) continue; 811 // already in list 812 return BTSTACK_BUSY; 813 } 814 entry = btstack_memory_sm_lookup_entry_get(); 815 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 816 entry->address_type = (bd_addr_type_t) address_type; 817 memcpy(entry->address, address, 6); 818 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 819 sm_run(); 820 return 0; 821 } 822 823 // CMAC Implementation using AES128 engine 824 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 825 int i; 826 int carry = 0; 827 for (i=len-1; i >= 0 ; i--){ 828 int new_carry = data[i] >> 7; 829 data[i] = data[i] << 1 | carry; 830 carry = new_carry; 831 } 832 } 833 834 // while x_state++ for an enum is possible in C, it isn't in C++. we use this helpers to avoid compile errors for now 835 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 836 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 837 } 838 static inline void dkg_next_state(void){ 839 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 840 } 841 static inline void rau_next_state(void){ 842 rau_state = (random_address_update_t) (((int)rau_state) + 1); 843 } 844 845 // CMAC calculation using AES Engine 846 847 static inline void sm_cmac_next_state(void){ 848 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 849 } 850 851 static int sm_cmac_last_block_complete(void){ 852 if (sm_cmac_message_len == 0) return 0; 853 return (sm_cmac_message_len & 0x0f) == 0; 854 } 855 856 int sm_cmac_ready(void){ 857 return sm_cmac_state == CMAC_IDLE; 858 } 859 860 // generic cmac calculation 861 void sm_cmac_general_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t hash[8])){ 862 // Generalized CMAC 863 memcpy(sm_cmac_k, key, 16); 864 memset(sm_cmac_x, 0, 16); 865 sm_cmac_block_current = 0; 866 sm_cmac_message_len = message_len; 867 sm_cmac_done_handler = done_callback; 868 sm_cmac_get_byte = get_byte_callback; 869 870 // step 2: n := ceil(len/const_Bsize); 871 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 872 873 // step 3: .. 874 if (sm_cmac_block_count==0){ 875 sm_cmac_block_count = 1; 876 } 877 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 878 879 // first, we need to compute l for k1, k2, and m_last 880 sm_cmac_state = CMAC_CALC_SUBKEYS; 881 882 // let's go 883 sm_run(); 884 } 885 886 // cmac for ATT Message signing 887 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 888 if (offset >= sm_cmac_message_len) { 889 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 890 return 0; 891 } 892 893 offset = sm_cmac_message_len - 1 - offset; 894 895 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 896 if (offset < 3){ 897 return sm_cmac_header[offset]; 898 } 899 int actual_message_len_incl_header = sm_cmac_message_len - 4; 900 if (offset < actual_message_len_incl_header){ 901 return sm_cmac_message[offset - 3]; 902 } 903 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 904 } 905 906 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 907 // ATT Message Signing 908 sm_cmac_header[0] = opcode; 909 little_endian_store_16(sm_cmac_header, 1, con_handle); 910 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 911 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 912 sm_cmac_message = message; 913 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 914 } 915 916 917 static void sm_cmac_handle_aes_engine_ready(void){ 918 switch (sm_cmac_state){ 919 case CMAC_CALC_SUBKEYS: { 920 sm_key_t const_zero; 921 memset(const_zero, 0, 16); 922 sm_cmac_next_state(); 923 sm_aes128_start(sm_cmac_k, const_zero, NULL); 924 break; 925 } 926 case CMAC_CALC_MI: { 927 int j; 928 sm_key_t y; 929 for (j=0;j<16;j++){ 930 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 931 } 932 sm_cmac_block_current++; 933 sm_cmac_next_state(); 934 sm_aes128_start(sm_cmac_k, y, NULL); 935 break; 936 } 937 case CMAC_CALC_MLAST: { 938 int i; 939 sm_key_t y; 940 for (i=0;i<16;i++){ 941 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 942 } 943 log_info_key("Y", y); 944 sm_cmac_block_current++; 945 sm_cmac_next_state(); 946 sm_aes128_start(sm_cmac_k, y, NULL); 947 break; 948 } 949 default: 950 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 951 break; 952 } 953 } 954 955 static void sm_cmac_handle_encryption_result(sm_key_t data){ 956 switch (sm_cmac_state){ 957 case CMAC_W4_SUBKEYS: { 958 sm_key_t k1; 959 memcpy(k1, data, 16); 960 sm_shift_left_by_one_bit_inplace(16, k1); 961 if (data[0] & 0x80){ 962 k1[15] ^= 0x87; 963 } 964 sm_key_t k2; 965 memcpy(k2, k1, 16); 966 sm_shift_left_by_one_bit_inplace(16, k2); 967 if (k1[0] & 0x80){ 968 k2[15] ^= 0x87; 969 } 970 971 log_info_key("k", sm_cmac_k); 972 log_info_key("k1", k1); 973 log_info_key("k2", k2); 974 975 // step 4: set m_last 976 int i; 977 if (sm_cmac_last_block_complete()){ 978 for (i=0;i<16;i++){ 979 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 980 } 981 } else { 982 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 983 for (i=0;i<16;i++){ 984 if (i < valid_octets_in_last_block){ 985 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 986 continue; 987 } 988 if (i == valid_octets_in_last_block){ 989 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 990 continue; 991 } 992 sm_cmac_m_last[i] = k2[i]; 993 } 994 } 995 996 // next 997 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 998 break; 999 } 1000 case CMAC_W4_MI: 1001 memcpy(sm_cmac_x, data, 16); 1002 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1003 break; 1004 case CMAC_W4_MLAST: 1005 // done 1006 log_info("Setting CMAC Engine to IDLE"); 1007 sm_cmac_state = CMAC_IDLE; 1008 log_info_key("CMAC", data); 1009 sm_cmac_done_handler(data); 1010 break; 1011 default: 1012 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1013 break; 1014 } 1015 } 1016 1017 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1018 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1019 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1020 switch (setup->sm_stk_generation_method){ 1021 case PK_RESP_INPUT: 1022 if (sm_conn->sm_role){ 1023 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1024 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1025 } else { 1026 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1027 } 1028 break; 1029 case PK_INIT_INPUT: 1030 if (sm_conn->sm_role){ 1031 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1032 } else { 1033 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1034 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1035 } 1036 break; 1037 case OK_BOTH_INPUT: 1038 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1039 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1040 break; 1041 case NK_BOTH_INPUT: 1042 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1043 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1044 break; 1045 case JUST_WORKS: 1046 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1047 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1048 break; 1049 case OOB: 1050 // client already provided OOB data, let's skip notification. 1051 break; 1052 } 1053 } 1054 1055 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1056 int recv_flags; 1057 if (sm_conn->sm_role){ 1058 // slave / responder 1059 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1060 } else { 1061 // master / initiator 1062 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1063 } 1064 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1065 return recv_flags == setup->sm_key_distribution_received_set; 1066 } 1067 1068 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1069 if (sm_active_connection == con_handle){ 1070 sm_timeout_stop(); 1071 sm_active_connection = 0; 1072 log_info("sm: connection 0x%x released setup context", con_handle); 1073 } 1074 } 1075 1076 static int sm_key_distribution_flags_for_auth_req(void){ 1077 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1078 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1079 // encryption information only if bonding requested 1080 flags |= SM_KEYDIST_ENC_KEY; 1081 } 1082 return flags; 1083 } 1084 1085 static void sm_reset_setup(void){ 1086 // fill in sm setup 1087 setup->sm_state_vars = 0; 1088 setup->sm_keypress_notification = 0xff; 1089 sm_reset_tk(); 1090 } 1091 1092 static void sm_init_setup(sm_connection_t * sm_conn){ 1093 1094 // fill in sm setup 1095 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1096 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1097 1098 // query client for OOB data 1099 int have_oob_data = 0; 1100 if (sm_get_oob_data) { 1101 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1102 } 1103 1104 sm_pairing_packet_t * local_packet; 1105 if (sm_conn->sm_role){ 1106 // slave 1107 local_packet = &setup->sm_s_pres; 1108 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1109 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1110 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1111 } else { 1112 // master 1113 local_packet = &setup->sm_m_preq; 1114 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1115 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1116 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1117 1118 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1119 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1120 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1121 } 1122 1123 uint8_t auth_req = sm_auth_req; 1124 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1125 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1126 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1127 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1128 } 1129 1130 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1131 1132 sm_pairing_packet_t * remote_packet; 1133 int remote_key_request; 1134 if (sm_conn->sm_role){ 1135 // slave / responder 1136 remote_packet = &setup->sm_m_preq; 1137 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1138 } else { 1139 // master / initiator 1140 remote_packet = &setup->sm_s_pres; 1141 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1142 } 1143 1144 // check key size 1145 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1146 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1147 1148 // decide on STK generation method 1149 sm_setup_tk(); 1150 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1151 1152 // check if STK generation method is acceptable by client 1153 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1154 1155 // identical to responder 1156 sm_setup_key_distribution(remote_key_request); 1157 1158 // JUST WORKS doens't provide authentication 1159 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1160 1161 return 0; 1162 } 1163 1164 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1165 1166 // cache and reset context 1167 int matched_device_id = sm_address_resolution_test; 1168 address_resolution_mode_t mode = sm_address_resolution_mode; 1169 void * context = sm_address_resolution_context; 1170 1171 // reset context 1172 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1173 sm_address_resolution_context = NULL; 1174 sm_address_resolution_test = -1; 1175 hci_con_handle_t con_handle = 0; 1176 1177 sm_connection_t * sm_connection; 1178 sm_key_t ltk; 1179 switch (mode){ 1180 case ADDRESS_RESOLUTION_GENERAL: 1181 break; 1182 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1183 sm_connection = (sm_connection_t *) context; 1184 con_handle = sm_connection->sm_handle; 1185 switch (event){ 1186 case ADDRESS_RESOLUTION_SUCEEDED: 1187 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1188 sm_connection->sm_le_db_index = matched_device_id; 1189 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1190 if (sm_connection->sm_role) break; 1191 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1192 sm_connection->sm_security_request_received = 0; 1193 sm_connection->sm_bonding_requested = 0; 1194 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1195 if (!sm_is_null_key(ltk)){ 1196 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1197 } else { 1198 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1199 } 1200 break; 1201 case ADDRESS_RESOLUTION_FAILED: 1202 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1203 if (sm_connection->sm_role) break; 1204 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1205 sm_connection->sm_security_request_received = 0; 1206 sm_connection->sm_bonding_requested = 0; 1207 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1208 break; 1209 } 1210 break; 1211 default: 1212 break; 1213 } 1214 1215 switch (event){ 1216 case ADDRESS_RESOLUTION_SUCEEDED: 1217 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1218 break; 1219 case ADDRESS_RESOLUTION_FAILED: 1220 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1221 break; 1222 } 1223 } 1224 1225 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1226 1227 int le_db_index = -1; 1228 1229 // lookup device based on IRK 1230 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1231 int i; 1232 for (i=0; i < le_device_db_count(); i++){ 1233 sm_key_t irk; 1234 bd_addr_t address; 1235 int address_type; 1236 le_device_db_info(i, &address_type, address, irk); 1237 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1238 log_info("sm: device found for IRK, updating"); 1239 le_db_index = i; 1240 break; 1241 } 1242 } 1243 } 1244 1245 // if not found, lookup via public address if possible 1246 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1247 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1248 int i; 1249 for (i=0; i < le_device_db_count(); i++){ 1250 bd_addr_t address; 1251 int address_type; 1252 le_device_db_info(i, &address_type, address, NULL); 1253 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1254 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1255 log_info("sm: device found for public address, updating"); 1256 le_db_index = i; 1257 break; 1258 } 1259 } 1260 } 1261 1262 // if not found, add to db 1263 if (le_db_index < 0) { 1264 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1265 } 1266 1267 if (le_db_index >= 0){ 1268 1269 // store local CSRK 1270 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1271 log_info("sm: store local CSRK"); 1272 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1273 le_device_db_local_counter_set(le_db_index, 0); 1274 } 1275 1276 // store remote CSRK 1277 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1278 log_info("sm: store remote CSRK"); 1279 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1280 le_device_db_remote_counter_set(le_db_index, 0); 1281 } 1282 1283 // store encryption information for secure connections: LTK generated by ECDH 1284 if (setup->sm_use_secure_connections){ 1285 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1286 uint8_t zero_rand[8]; 1287 memset(zero_rand, 0, 8); 1288 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1289 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1290 } 1291 1292 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1293 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1294 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1295 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1296 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1297 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1298 1299 } 1300 } 1301 1302 // keep le_db_index 1303 sm_conn->sm_le_db_index = le_db_index; 1304 } 1305 1306 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1307 setup->sm_pairing_failed_reason = reason; 1308 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1309 } 1310 1311 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1312 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1313 } 1314 1315 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1316 1317 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1318 static int sm_passkey_used(stk_generation_method_t method); 1319 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1320 1321 static void sm_log_ec_keypair(void){ 1322 log_info("Elliptic curve: d"); 1323 log_info_hexdump(ec_d,32); 1324 log_info("Elliptic curve: X"); 1325 log_info_hexdump(ec_qx,32); 1326 log_info("Elliptic curve: Y"); 1327 log_info_hexdump(ec_qy,32); 1328 } 1329 1330 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1331 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1332 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1333 } else { 1334 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1335 } 1336 } 1337 1338 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1339 if (sm_conn->sm_role){ 1340 // Responder 1341 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1342 } else { 1343 // Initiator role 1344 switch (setup->sm_stk_generation_method){ 1345 case JUST_WORKS: 1346 sm_sc_prepare_dhkey_check(sm_conn); 1347 break; 1348 1349 case NK_BOTH_INPUT: 1350 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1351 break; 1352 case PK_INIT_INPUT: 1353 case PK_RESP_INPUT: 1354 case OK_BOTH_INPUT: 1355 if (setup->sm_passkey_bit < 20) { 1356 sm_sc_start_calculating_local_confirm(sm_conn); 1357 } else { 1358 sm_sc_prepare_dhkey_check(sm_conn); 1359 } 1360 break; 1361 case OOB: 1362 // TODO: implement SC OOB 1363 break; 1364 } 1365 } 1366 } 1367 1368 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1369 return sm_cmac_sc_buffer[offset]; 1370 } 1371 1372 static void sm_sc_cmac_done(uint8_t * hash){ 1373 log_info("sm_sc_cmac_done: "); 1374 log_info_hexdump(hash, 16); 1375 1376 sm_connection_t * sm_conn = sm_cmac_connection; 1377 sm_cmac_connection = NULL; 1378 link_key_type_t link_key_type; 1379 1380 switch (sm_conn->sm_engine_state){ 1381 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1382 memcpy(setup->sm_local_confirm, hash, 16); 1383 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1384 break; 1385 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1386 // check 1387 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1388 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1389 break; 1390 } 1391 sm_sc_state_after_receiving_random(sm_conn); 1392 break; 1393 case SM_SC_W4_CALCULATE_G2: { 1394 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1395 big_endian_store_32(setup->sm_tk, 12, vab); 1396 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1397 sm_trigger_user_response(sm_conn); 1398 break; 1399 } 1400 case SM_SC_W4_CALCULATE_F5_SALT: 1401 memcpy(setup->sm_t, hash, 16); 1402 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1403 break; 1404 case SM_SC_W4_CALCULATE_F5_MACKEY: 1405 memcpy(setup->sm_mackey, hash, 16); 1406 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1407 break; 1408 case SM_SC_W4_CALCULATE_F5_LTK: 1409 memcpy(setup->sm_ltk, hash, 16); 1410 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1411 break; 1412 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1413 memcpy(setup->sm_local_dhkey_check, hash, 16); 1414 if (sm_conn->sm_role){ 1415 // responder 1416 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1417 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1418 } else { 1419 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1420 } 1421 } else { 1422 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1423 } 1424 break; 1425 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1426 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1427 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1428 break; 1429 } 1430 if (sm_conn->sm_role){ 1431 // responder 1432 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1433 } else { 1434 // initiator 1435 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1436 } 1437 break; 1438 case SM_SC_W4_CALCULATE_H6_ILK: 1439 memcpy(setup->sm_t, hash, 16); 1440 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1441 break; 1442 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1443 reverse_128(hash, setup->sm_t); 1444 link_key_type = sm_conn->sm_connection_authenticated ? 1445 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1446 if (sm_conn->sm_role){ 1447 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1448 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1449 } else { 1450 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1451 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1452 } 1453 sm_done_for_handle(sm_conn->sm_handle); 1454 break; 1455 default: 1456 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1457 break; 1458 } 1459 sm_run(); 1460 } 1461 1462 static void f4_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, uint8_t z){ 1463 const uint16_t message_len = 65; 1464 sm_cmac_connection = sm_conn; 1465 memcpy(sm_cmac_sc_buffer, u, 32); 1466 memcpy(sm_cmac_sc_buffer+32, v, 32); 1467 sm_cmac_sc_buffer[64] = z; 1468 log_info("f4 key"); 1469 log_info_hexdump(x, 16); 1470 log_info("f4 message"); 1471 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1472 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1473 } 1474 1475 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1476 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1477 static const uint8_t f5_length[] = { 0x01, 0x00}; 1478 1479 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1480 #ifdef USE_MBEDTLS_FOR_ECDH 1481 // da * Pb 1482 mbedtls_mpi d; 1483 mbedtls_ecp_point Q; 1484 mbedtls_ecp_point DH; 1485 mbedtls_mpi_init(&d); 1486 mbedtls_ecp_point_init(&Q); 1487 mbedtls_ecp_point_init(&DH); 1488 mbedtls_mpi_read_binary(&d, ec_d, 32); 1489 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1490 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1491 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1492 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1493 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1494 mbedtls_mpi_free(&d); 1495 mbedtls_ecp_point_free(&Q); 1496 mbedtls_ecp_point_free(&DH); 1497 #endif 1498 log_info("dhkey"); 1499 log_info_hexdump(dhkey, 32); 1500 } 1501 1502 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1503 // calculate DHKEY 1504 sm_key256_t dhkey; 1505 sm_sc_calculate_dhkey(dhkey); 1506 1507 // calculate salt for f5 1508 const uint16_t message_len = 32; 1509 sm_cmac_connection = sm_conn; 1510 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1511 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1512 } 1513 1514 static inline void f5_mackkey(sm_connection_t * sm_conn, sm_key_t t, const sm_key_t n1, const sm_key_t n2, const sm_key56_t a1, const sm_key56_t a2){ 1515 const uint16_t message_len = 53; 1516 sm_cmac_connection = sm_conn; 1517 1518 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1519 sm_cmac_sc_buffer[0] = 0; 1520 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1521 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1522 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1523 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1524 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1525 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1526 log_info("f5 key"); 1527 log_info_hexdump(t, 16); 1528 log_info("f5 message for MacKey"); 1529 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1530 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1531 } 1532 1533 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1534 sm_key56_t bd_addr_master, bd_addr_slave; 1535 bd_addr_master[0] = setup->sm_m_addr_type; 1536 bd_addr_slave[0] = setup->sm_s_addr_type; 1537 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1538 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1539 if (sm_conn->sm_role){ 1540 // responder 1541 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1542 } else { 1543 // initiator 1544 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1545 } 1546 } 1547 1548 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1549 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1550 const uint16_t message_len = 53; 1551 sm_cmac_connection = sm_conn; 1552 sm_cmac_sc_buffer[0] = 1; 1553 // 1..52 setup before 1554 log_info("f5 key"); 1555 log_info_hexdump(t, 16); 1556 log_info("f5 message for LTK"); 1557 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1558 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1559 } 1560 1561 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1562 f5_ltk(sm_conn, setup->sm_t); 1563 } 1564 1565 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w, const sm_key_t n1, const sm_key_t n2, const sm_key_t r, const sm_key24_t io_cap, const sm_key56_t a1, const sm_key56_t a2){ 1566 const uint16_t message_len = 65; 1567 sm_cmac_connection = sm_conn; 1568 memcpy(sm_cmac_sc_buffer, n1, 16); 1569 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1570 memcpy(sm_cmac_sc_buffer+32, r, 16); 1571 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1572 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1573 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1574 log_info("f6 key"); 1575 log_info_hexdump(w, 16); 1576 log_info("f6 message"); 1577 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1578 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1579 } 1580 1581 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1582 // - U is 256 bits 1583 // - V is 256 bits 1584 // - X is 128 bits 1585 // - Y is 128 bits 1586 static void g2_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 1587 const uint16_t message_len = 80; 1588 sm_cmac_connection = sm_conn; 1589 memcpy(sm_cmac_sc_buffer, u, 32); 1590 memcpy(sm_cmac_sc_buffer+32, v, 32); 1591 memcpy(sm_cmac_sc_buffer+64, y, 16); 1592 log_info("g2 key"); 1593 log_info_hexdump(x, 16); 1594 log_info("g2 message"); 1595 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1596 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1597 } 1598 1599 static void g2_calculate(sm_connection_t * sm_conn) { 1600 // calc Va if numeric comparison 1601 if (sm_conn->sm_role){ 1602 // responder 1603 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1604 } else { 1605 // initiator 1606 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1607 } 1608 } 1609 1610 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1611 uint8_t z = 0; 1612 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1613 // some form of passkey 1614 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1615 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1616 setup->sm_passkey_bit++; 1617 } 1618 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1619 } 1620 1621 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1622 uint8_t z = 0; 1623 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1624 // some form of passkey 1625 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1626 // sm_passkey_bit was increased before sending confirm value 1627 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1628 } 1629 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1630 } 1631 1632 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1633 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1634 } 1635 1636 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1637 // calculate DHKCheck 1638 sm_key56_t bd_addr_master, bd_addr_slave; 1639 bd_addr_master[0] = setup->sm_m_addr_type; 1640 bd_addr_slave[0] = setup->sm_s_addr_type; 1641 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1642 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1643 uint8_t iocap_a[3]; 1644 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1645 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1646 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1647 uint8_t iocap_b[3]; 1648 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1649 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1650 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1651 if (sm_conn->sm_role){ 1652 // responder 1653 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1654 } else { 1655 // initiator 1656 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1657 } 1658 } 1659 1660 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1661 // validate E = f6() 1662 sm_key56_t bd_addr_master, bd_addr_slave; 1663 bd_addr_master[0] = setup->sm_m_addr_type; 1664 bd_addr_slave[0] = setup->sm_s_addr_type; 1665 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1666 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1667 1668 uint8_t iocap_a[3]; 1669 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1670 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1671 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1672 uint8_t iocap_b[3]; 1673 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1674 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1675 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1676 if (sm_conn->sm_role){ 1677 // responder 1678 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1679 } else { 1680 // initiator 1681 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1682 } 1683 } 1684 1685 1686 // 1687 // Link Key Conversion Function h6 1688 // 1689 // h6(W, keyID) = AES-CMACW(keyID) 1690 // - W is 128 bits 1691 // - keyID is 32 bits 1692 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1693 const uint16_t message_len = 4; 1694 sm_cmac_connection = sm_conn; 1695 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1696 log_info("h6 key"); 1697 log_info_hexdump(w, 16); 1698 log_info("h6 message"); 1699 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1700 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1701 } 1702 1703 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1704 h6_engine(sm_conn, setup->sm_ltk, 0x746D7031); // "tmp1" 1705 } 1706 1707 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1708 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1709 } 1710 1711 #endif 1712 1713 // key management legacy connections: 1714 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1715 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1716 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1717 // - responder reconnects: responder uses LTK receveived from master 1718 1719 // key management secure connections: 1720 // - both devices store same LTK from ECDH key exchange. 1721 1722 static void sm_load_security_info(sm_connection_t * sm_connection){ 1723 int encryption_key_size; 1724 int authenticated; 1725 int authorized; 1726 1727 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1728 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1729 &encryption_key_size, &authenticated, &authorized); 1730 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1731 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1732 sm_connection->sm_connection_authenticated = authenticated; 1733 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1734 } 1735 1736 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1737 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1738 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1739 // re-establish used key encryption size 1740 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1741 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1742 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1743 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1744 log_info("sm: received ltk request with key size %u, authenticated %u", 1745 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1746 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1747 } 1748 1749 static void sm_run(void){ 1750 1751 btstack_linked_list_iterator_t it; 1752 1753 // assert that we can send at least commands 1754 if (!hci_can_send_command_packet_now()) return; 1755 1756 // 1757 // non-connection related behaviour 1758 // 1759 1760 // distributed key generation 1761 switch (dkg_state){ 1762 case DKG_CALC_IRK: 1763 // already busy? 1764 if (sm_aes128_state == SM_AES128_IDLE) { 1765 // IRK = d1(IR, 1, 0) 1766 sm_key_t d1_prime; 1767 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1768 dkg_next_state(); 1769 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1770 return; 1771 } 1772 break; 1773 case DKG_CALC_DHK: 1774 // already busy? 1775 if (sm_aes128_state == SM_AES128_IDLE) { 1776 // DHK = d1(IR, 3, 0) 1777 sm_key_t d1_prime; 1778 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1779 dkg_next_state(); 1780 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1781 return; 1782 } 1783 break; 1784 default: 1785 break; 1786 } 1787 1788 #ifdef USE_MBEDTLS_FOR_ECDH 1789 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1790 sm_random_start(NULL); 1791 return; 1792 } 1793 #endif 1794 1795 // random address updates 1796 switch (rau_state){ 1797 case RAU_GET_RANDOM: 1798 rau_next_state(); 1799 sm_random_start(NULL); 1800 return; 1801 case RAU_GET_ENC: 1802 // already busy? 1803 if (sm_aes128_state == SM_AES128_IDLE) { 1804 sm_key_t r_prime; 1805 sm_ah_r_prime(sm_random_address, r_prime); 1806 rau_next_state(); 1807 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1808 return; 1809 } 1810 break; 1811 case RAU_SET_ADDRESS: 1812 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1813 rau_state = RAU_IDLE; 1814 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1815 return; 1816 default: 1817 break; 1818 } 1819 1820 // CMAC 1821 switch (sm_cmac_state){ 1822 case CMAC_CALC_SUBKEYS: 1823 case CMAC_CALC_MI: 1824 case CMAC_CALC_MLAST: 1825 // already busy? 1826 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1827 sm_cmac_handle_aes_engine_ready(); 1828 return; 1829 default: 1830 break; 1831 } 1832 1833 // CSRK Lookup 1834 // -- if csrk lookup ready, find connection that require csrk lookup 1835 if (sm_address_resolution_idle()){ 1836 hci_connections_get_iterator(&it); 1837 while(btstack_linked_list_iterator_has_next(&it)){ 1838 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1839 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1840 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1841 // and start lookup 1842 sm_address_resolution_start_lookup(sm_connection->sm_peer_addr_type, sm_connection->sm_handle, sm_connection->sm_peer_address, ADDRESS_RESOLUTION_FOR_CONNECTION, sm_connection); 1843 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1844 break; 1845 } 1846 } 1847 } 1848 1849 // -- if csrk lookup ready, resolved addresses for received addresses 1850 if (sm_address_resolution_idle()) { 1851 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1852 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1853 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1854 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1855 btstack_memory_sm_lookup_entry_free(entry); 1856 } 1857 } 1858 1859 // -- Continue with CSRK device lookup by public or resolvable private address 1860 if (!sm_address_resolution_idle()){ 1861 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1862 while (sm_address_resolution_test < le_device_db_count()){ 1863 int addr_type; 1864 bd_addr_t addr; 1865 sm_key_t irk; 1866 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1867 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1868 1869 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1870 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1871 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1872 break; 1873 } 1874 1875 if (sm_address_resolution_addr_type == 0){ 1876 sm_address_resolution_test++; 1877 continue; 1878 } 1879 1880 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1881 1882 log_info("LE Device Lookup: calculate AH"); 1883 log_info_key("IRK", irk); 1884 1885 sm_key_t r_prime; 1886 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1887 sm_address_resolution_ah_calculation_active = 1; 1888 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1889 return; 1890 } 1891 1892 if (sm_address_resolution_test >= le_device_db_count()){ 1893 log_info("LE Device Lookup: not found"); 1894 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1895 } 1896 } 1897 1898 1899 // 1900 // active connection handling 1901 // -- use loop to handle next connection if lock on setup context is released 1902 1903 while (1) { 1904 1905 // Find connections that requires setup context and make active if no other is locked 1906 hci_connections_get_iterator(&it); 1907 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1908 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1909 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1910 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1911 int done = 1; 1912 int err; 1913 switch (sm_connection->sm_engine_state) { 1914 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1915 // send packet if possible, 1916 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1917 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1918 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1919 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1920 } else { 1921 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1922 } 1923 // don't lock sxetup context yet 1924 done = 0; 1925 break; 1926 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1927 sm_reset_setup(); 1928 sm_init_setup(sm_connection); 1929 // recover pairing request 1930 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1931 err = sm_stk_generation_init(sm_connection); 1932 if (err){ 1933 setup->sm_pairing_failed_reason = err; 1934 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1935 break; 1936 } 1937 sm_timeout_start(sm_connection); 1938 // generate random number first, if we need to show passkey 1939 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1940 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1941 break; 1942 } 1943 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1944 break; 1945 case SM_INITIATOR_PH0_HAS_LTK: 1946 sm_reset_setup(); 1947 sm_load_security_info(sm_connection); 1948 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1949 break; 1950 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 1951 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1952 switch (sm_connection->sm_irk_lookup_state){ 1953 case IRK_LOOKUP_SUCCEEDED: 1954 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 1955 sm_reset_setup(); 1956 sm_load_security_info(sm_connection); 1957 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 1958 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 1959 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 1960 break; 1961 } 1962 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 1963 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1964 // don't lock setup context yet 1965 done = 0; 1966 break; 1967 case IRK_LOOKUP_FAILED: 1968 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1969 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1970 // don't lock setup context yet 1971 done = 0; 1972 break; 1973 default: 1974 // just wait until IRK lookup is completed 1975 // don't lock setup context yet 1976 done = 0; 1977 break; 1978 } 1979 #endif 1980 break; 1981 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1982 sm_reset_setup(); 1983 sm_init_setup(sm_connection); 1984 sm_timeout_start(sm_connection); 1985 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1986 break; 1987 default: 1988 done = 0; 1989 break; 1990 } 1991 if (done){ 1992 sm_active_connection = sm_connection->sm_handle; 1993 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1994 } 1995 } 1996 1997 // 1998 // active connection handling 1999 // 2000 2001 if (sm_active_connection == 0) return; 2002 2003 // assert that we could send a SM PDU - not needed for all of the following 2004 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2005 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2006 return; 2007 } 2008 2009 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2010 if (!connection) return; 2011 2012 // send keypress notifications 2013 if (setup->sm_keypress_notification != 0xff){ 2014 uint8_t buffer[2]; 2015 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2016 buffer[1] = setup->sm_keypress_notification; 2017 setup->sm_keypress_notification = 0xff; 2018 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2019 return; 2020 } 2021 2022 sm_key_t plaintext; 2023 int key_distribution_flags; 2024 2025 log_info("sm_run: state %u", connection->sm_engine_state); 2026 2027 // responding state 2028 switch (connection->sm_engine_state){ 2029 2030 // general 2031 case SM_GENERAL_SEND_PAIRING_FAILED: { 2032 uint8_t buffer[2]; 2033 buffer[0] = SM_CODE_PAIRING_FAILED; 2034 buffer[1] = setup->sm_pairing_failed_reason; 2035 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2036 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2037 sm_done_for_handle(connection->sm_handle); 2038 break; 2039 } 2040 2041 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2042 case SM_SC_W2_GET_RANDOM_A: 2043 sm_random_start(connection); 2044 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2045 break; 2046 case SM_SC_W2_GET_RANDOM_B: 2047 sm_random_start(connection); 2048 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2049 break; 2050 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2051 if (!sm_cmac_ready()) break; 2052 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2053 sm_sc_calculate_local_confirm(connection); 2054 break; 2055 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2056 if (!sm_cmac_ready()) break; 2057 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2058 sm_sc_calculate_remote_confirm(connection); 2059 break; 2060 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2061 if (!sm_cmac_ready()) break; 2062 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2063 sm_sc_calculate_f6_for_dhkey_check(connection); 2064 break; 2065 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2066 if (!sm_cmac_ready()) break; 2067 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2068 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2069 break; 2070 case SM_SC_W2_CALCULATE_F5_SALT: 2071 if (!sm_cmac_ready()) break; 2072 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2073 f5_calculate_salt(connection); 2074 break; 2075 case SM_SC_W2_CALCULATE_F5_MACKEY: 2076 if (!sm_cmac_ready()) break; 2077 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2078 f5_calculate_mackey(connection); 2079 break; 2080 case SM_SC_W2_CALCULATE_F5_LTK: 2081 if (!sm_cmac_ready()) break; 2082 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2083 f5_calculate_ltk(connection); 2084 break; 2085 case SM_SC_W2_CALCULATE_G2: 2086 if (!sm_cmac_ready()) break; 2087 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2088 g2_calculate(connection); 2089 break; 2090 case SM_SC_W2_CALCULATE_H6_ILK: 2091 if (!sm_cmac_ready()) break; 2092 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2093 h6_calculate_ilk(connection); 2094 break; 2095 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2096 if (!sm_cmac_ready()) break; 2097 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2098 h6_calculate_br_edr_link_key(connection); 2099 break; 2100 2101 #endif 2102 // initiator side 2103 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2104 sm_key_t peer_ltk_flipped; 2105 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2106 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2107 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2108 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2109 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2110 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2111 return; 2112 } 2113 2114 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2115 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2116 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2117 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2118 sm_timeout_reset(connection); 2119 break; 2120 2121 // responder side 2122 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2123 connection->sm_engine_state = SM_RESPONDER_IDLE; 2124 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2125 sm_done_for_handle(connection->sm_handle); 2126 return; 2127 2128 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2129 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2130 uint8_t buffer[65]; 2131 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2132 // 2133 reverse_256(ec_qx, &buffer[1]); 2134 reverse_256(ec_qy, &buffer[33]); 2135 2136 // stk generation method 2137 // passkey entry: notify app to show passkey or to request passkey 2138 switch (setup->sm_stk_generation_method){ 2139 case JUST_WORKS: 2140 case NK_BOTH_INPUT: 2141 if (connection->sm_role){ 2142 // responder 2143 sm_sc_start_calculating_local_confirm(connection); 2144 } else { 2145 // initiator 2146 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2147 } 2148 break; 2149 case PK_INIT_INPUT: 2150 case PK_RESP_INPUT: 2151 case OK_BOTH_INPUT: 2152 // use random TK for display 2153 memcpy(setup->sm_ra, setup->sm_tk, 16); 2154 memcpy(setup->sm_rb, setup->sm_tk, 16); 2155 setup->sm_passkey_bit = 0; 2156 2157 if (connection->sm_role){ 2158 // responder 2159 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2160 } else { 2161 // initiator 2162 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2163 } 2164 sm_trigger_user_response(connection); 2165 break; 2166 case OOB: 2167 // TODO: implement SC OOB 2168 break; 2169 } 2170 2171 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2172 sm_timeout_reset(connection); 2173 break; 2174 } 2175 case SM_SC_SEND_CONFIRMATION: { 2176 uint8_t buffer[17]; 2177 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2178 reverse_128(setup->sm_local_confirm, &buffer[1]); 2179 if (connection->sm_role){ 2180 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2181 } else { 2182 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2183 } 2184 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2185 sm_timeout_reset(connection); 2186 break; 2187 } 2188 case SM_SC_SEND_PAIRING_RANDOM: { 2189 uint8_t buffer[17]; 2190 buffer[0] = SM_CODE_PAIRING_RANDOM; 2191 reverse_128(setup->sm_local_nonce, &buffer[1]); 2192 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2193 if (connection->sm_role){ 2194 // responder 2195 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2196 } else { 2197 // initiator 2198 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2199 } 2200 } else { 2201 if (connection->sm_role){ 2202 // responder 2203 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2204 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2205 } else { 2206 sm_sc_prepare_dhkey_check(connection); 2207 } 2208 } else { 2209 // initiator 2210 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2211 } 2212 } 2213 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2214 sm_timeout_reset(connection); 2215 break; 2216 } 2217 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2218 uint8_t buffer[17]; 2219 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2220 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2221 2222 if (connection->sm_role){ 2223 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2224 } else { 2225 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2226 } 2227 2228 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2229 sm_timeout_reset(connection); 2230 break; 2231 } 2232 2233 #endif 2234 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2235 // echo initiator for now 2236 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2237 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2238 2239 if (setup->sm_use_secure_connections){ 2240 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2241 // skip LTK/EDIV for SC 2242 log_info("sm: dropping encryption information flag"); 2243 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2244 } else { 2245 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2246 } 2247 2248 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq) & key_distribution_flags); 2249 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq) & key_distribution_flags); 2250 // update key distribution after ENC was dropped 2251 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2252 2253 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2254 sm_timeout_reset(connection); 2255 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2256 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2257 sm_trigger_user_response(connection); 2258 } 2259 return; 2260 2261 case SM_PH2_SEND_PAIRING_RANDOM: { 2262 uint8_t buffer[17]; 2263 buffer[0] = SM_CODE_PAIRING_RANDOM; 2264 reverse_128(setup->sm_local_random, &buffer[1]); 2265 if (connection->sm_role){ 2266 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2267 } else { 2268 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2269 } 2270 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2271 sm_timeout_reset(connection); 2272 break; 2273 } 2274 2275 case SM_PH2_GET_RANDOM_TK: 2276 case SM_PH2_C1_GET_RANDOM_A: 2277 case SM_PH2_C1_GET_RANDOM_B: 2278 case SM_PH3_GET_RANDOM: 2279 case SM_PH3_GET_DIV: 2280 sm_next_responding_state(connection); 2281 sm_random_start(connection); 2282 return; 2283 2284 case SM_PH2_C1_GET_ENC_B: 2285 case SM_PH2_C1_GET_ENC_D: 2286 // already busy? 2287 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2288 sm_next_responding_state(connection); 2289 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2290 return; 2291 2292 case SM_PH3_LTK_GET_ENC: 2293 case SM_RESPONDER_PH4_LTK_GET_ENC: 2294 // already busy? 2295 if (sm_aes128_state == SM_AES128_IDLE) { 2296 sm_key_t d_prime; 2297 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2298 sm_next_responding_state(connection); 2299 sm_aes128_start(sm_persistent_er, d_prime, connection); 2300 return; 2301 } 2302 break; 2303 2304 case SM_PH3_CSRK_GET_ENC: 2305 // already busy? 2306 if (sm_aes128_state == SM_AES128_IDLE) { 2307 sm_key_t d_prime; 2308 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2309 sm_next_responding_state(connection); 2310 sm_aes128_start(sm_persistent_er, d_prime, connection); 2311 return; 2312 } 2313 break; 2314 2315 case SM_PH2_C1_GET_ENC_C: 2316 // already busy? 2317 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2318 // calculate m_confirm using aes128 engine - step 1 2319 sm_c1_t1(setup->sm_peer_random, (uint8_t*) &setup->sm_m_preq, (uint8_t*) &setup->sm_s_pres, setup->sm_m_addr_type, setup->sm_s_addr_type, plaintext); 2320 sm_next_responding_state(connection); 2321 sm_aes128_start(setup->sm_tk, plaintext, connection); 2322 break; 2323 case SM_PH2_C1_GET_ENC_A: 2324 // already busy? 2325 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2326 // calculate confirm using aes128 engine - step 1 2327 sm_c1_t1(setup->sm_local_random, (uint8_t*) &setup->sm_m_preq, (uint8_t*) &setup->sm_s_pres, setup->sm_m_addr_type, setup->sm_s_addr_type, plaintext); 2328 sm_next_responding_state(connection); 2329 sm_aes128_start(setup->sm_tk, plaintext, connection); 2330 break; 2331 case SM_PH2_CALC_STK: 2332 // already busy? 2333 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2334 // calculate STK 2335 if (connection->sm_role){ 2336 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2337 } else { 2338 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2339 } 2340 sm_next_responding_state(connection); 2341 sm_aes128_start(setup->sm_tk, plaintext, connection); 2342 break; 2343 case SM_PH3_Y_GET_ENC: 2344 // already busy? 2345 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2346 // PH3B2 - calculate Y from - enc 2347 // Y = dm(DHK, Rand) 2348 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2349 sm_next_responding_state(connection); 2350 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2351 return; 2352 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2353 uint8_t buffer[17]; 2354 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2355 reverse_128(setup->sm_local_confirm, &buffer[1]); 2356 if (connection->sm_role){ 2357 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2358 } else { 2359 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2360 } 2361 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2362 sm_timeout_reset(connection); 2363 return; 2364 } 2365 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2366 sm_key_t stk_flipped; 2367 reverse_128(setup->sm_ltk, stk_flipped); 2368 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2369 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2370 return; 2371 } 2372 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2373 sm_key_t stk_flipped; 2374 reverse_128(setup->sm_ltk, stk_flipped); 2375 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2376 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2377 return; 2378 } 2379 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2380 sm_key_t ltk_flipped; 2381 reverse_128(setup->sm_ltk, ltk_flipped); 2382 connection->sm_engine_state = SM_RESPONDER_IDLE; 2383 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2384 return; 2385 } 2386 case SM_RESPONDER_PH4_Y_GET_ENC: 2387 // already busy? 2388 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2389 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2390 // Y = dm(DHK, Rand) 2391 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2392 sm_next_responding_state(connection); 2393 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2394 return; 2395 2396 case SM_PH3_DISTRIBUTE_KEYS: 2397 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2398 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2399 uint8_t buffer[17]; 2400 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2401 reverse_128(setup->sm_ltk, &buffer[1]); 2402 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2403 sm_timeout_reset(connection); 2404 return; 2405 } 2406 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2407 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2408 uint8_t buffer[11]; 2409 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2410 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2411 reverse_64(setup->sm_local_rand, &buffer[3]); 2412 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2413 sm_timeout_reset(connection); 2414 return; 2415 } 2416 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2417 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2418 uint8_t buffer[17]; 2419 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2420 reverse_128(sm_persistent_irk, &buffer[1]); 2421 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2422 sm_timeout_reset(connection); 2423 return; 2424 } 2425 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2426 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2427 bd_addr_t local_address; 2428 uint8_t buffer[8]; 2429 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2430 gap_advertisements_get_address(&buffer[1], local_address); 2431 reverse_bd_addr(local_address, &buffer[2]); 2432 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2433 sm_timeout_reset(connection); 2434 return; 2435 } 2436 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2437 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2438 2439 // hack to reproduce test runs 2440 if (test_use_fixed_local_csrk){ 2441 memset(setup->sm_local_csrk, 0xcc, 16); 2442 } 2443 2444 uint8_t buffer[17]; 2445 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2446 reverse_128(setup->sm_local_csrk, &buffer[1]); 2447 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2448 sm_timeout_reset(connection); 2449 return; 2450 } 2451 2452 // keys are sent 2453 if (connection->sm_role){ 2454 // slave -> receive master keys if any 2455 if (sm_key_distribution_all_received(connection)){ 2456 sm_key_distribution_handle_all_received(connection); 2457 connection->sm_engine_state = SM_RESPONDER_IDLE; 2458 sm_done_for_handle(connection->sm_handle); 2459 } else { 2460 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2461 } 2462 } else { 2463 // master -> all done 2464 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2465 sm_done_for_handle(connection->sm_handle); 2466 } 2467 break; 2468 2469 default: 2470 break; 2471 } 2472 2473 // check again if active connection was released 2474 if (sm_active_connection) break; 2475 } 2476 } 2477 2478 // note: aes engine is ready as we just got the aes result 2479 static void sm_handle_encryption_result(uint8_t * data){ 2480 2481 sm_aes128_state = SM_AES128_IDLE; 2482 2483 if (sm_address_resolution_ah_calculation_active){ 2484 sm_address_resolution_ah_calculation_active = 0; 2485 // compare calulated address against connecting device 2486 uint8_t hash[3]; 2487 reverse_24(data, hash); 2488 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2489 log_info("LE Device Lookup: matched resolvable private address"); 2490 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2491 return; 2492 } 2493 // no match, try next 2494 sm_address_resolution_test++; 2495 return; 2496 } 2497 2498 switch (dkg_state){ 2499 case DKG_W4_IRK: 2500 reverse_128(data, sm_persistent_irk); 2501 log_info_key("irk", sm_persistent_irk); 2502 dkg_next_state(); 2503 return; 2504 case DKG_W4_DHK: 2505 reverse_128(data, sm_persistent_dhk); 2506 log_info_key("dhk", sm_persistent_dhk); 2507 dkg_next_state(); 2508 // SM Init Finished 2509 return; 2510 default: 2511 break; 2512 } 2513 2514 switch (rau_state){ 2515 case RAU_W4_ENC: 2516 reverse_24(data, &sm_random_address[3]); 2517 rau_next_state(); 2518 return; 2519 default: 2520 break; 2521 } 2522 2523 switch (sm_cmac_state){ 2524 case CMAC_W4_SUBKEYS: 2525 case CMAC_W4_MI: 2526 case CMAC_W4_MLAST: 2527 { 2528 sm_key_t t; 2529 reverse_128(data, t); 2530 sm_cmac_handle_encryption_result(t); 2531 } 2532 return; 2533 default: 2534 break; 2535 } 2536 2537 // retrieve sm_connection provided to sm_aes128_start_encryption 2538 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2539 if (!connection) return; 2540 switch (connection->sm_engine_state){ 2541 case SM_PH2_C1_W4_ENC_A: 2542 case SM_PH2_C1_W4_ENC_C: 2543 { 2544 sm_key_t t2; 2545 reverse_128(data, t2); 2546 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2547 } 2548 sm_next_responding_state(connection); 2549 return; 2550 case SM_PH2_C1_W4_ENC_B: 2551 reverse_128(data, setup->sm_local_confirm); 2552 log_info_key("c1!", setup->sm_local_confirm); 2553 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2554 return; 2555 case SM_PH2_C1_W4_ENC_D: 2556 { 2557 sm_key_t peer_confirm_test; 2558 reverse_128(data, peer_confirm_test); 2559 log_info_key("c1!", peer_confirm_test); 2560 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2561 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2562 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2563 return; 2564 } 2565 if (connection->sm_role){ 2566 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2567 } else { 2568 connection->sm_engine_state = SM_PH2_CALC_STK; 2569 } 2570 } 2571 return; 2572 case SM_PH2_W4_STK: 2573 reverse_128(data, setup->sm_ltk); 2574 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2575 log_info_key("stk", setup->sm_ltk); 2576 if (connection->sm_role){ 2577 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2578 } else { 2579 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2580 } 2581 return; 2582 case SM_PH3_Y_W4_ENC:{ 2583 sm_key_t y128; 2584 reverse_128(data, y128); 2585 setup->sm_local_y = big_endian_read_16(y128, 14); 2586 log_info_hex16("y", setup->sm_local_y); 2587 // PH3B3 - calculate EDIV 2588 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2589 log_info_hex16("ediv", setup->sm_local_ediv); 2590 // PH3B4 - calculate LTK - enc 2591 // LTK = d1(ER, DIV, 0)) 2592 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2593 return; 2594 } 2595 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2596 sm_key_t y128; 2597 reverse_128(data, y128); 2598 setup->sm_local_y = big_endian_read_16(y128, 14); 2599 log_info_hex16("y", setup->sm_local_y); 2600 2601 // PH3B3 - calculate DIV 2602 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2603 log_info_hex16("ediv", setup->sm_local_ediv); 2604 // PH3B4 - calculate LTK - enc 2605 // LTK = d1(ER, DIV, 0)) 2606 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2607 return; 2608 } 2609 case SM_PH3_LTK_W4_ENC: 2610 reverse_128(data, setup->sm_ltk); 2611 log_info_key("ltk", setup->sm_ltk); 2612 // calc CSRK next 2613 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2614 return; 2615 case SM_PH3_CSRK_W4_ENC: 2616 reverse_128(data, setup->sm_local_csrk); 2617 log_info_key("csrk", setup->sm_local_csrk); 2618 if (setup->sm_key_distribution_send_set){ 2619 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2620 } else { 2621 // no keys to send, just continue 2622 if (connection->sm_role){ 2623 // slave -> receive master keys 2624 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2625 } else { 2626 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2627 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2628 } else { 2629 // master -> all done 2630 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2631 sm_done_for_handle(connection->sm_handle); 2632 } 2633 } 2634 } 2635 return; 2636 case SM_RESPONDER_PH4_LTK_W4_ENC: 2637 reverse_128(data, setup->sm_ltk); 2638 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2639 log_info_key("ltk", setup->sm_ltk); 2640 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2641 return; 2642 default: 2643 break; 2644 } 2645 } 2646 2647 #ifdef USE_MBEDTLS_FOR_ECDH 2648 2649 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2650 int offset = setup->sm_passkey_bit; 2651 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2652 while (size) { 2653 if (offset < 32){ 2654 *buffer++ = setup->sm_peer_qx[offset++]; 2655 } else { 2656 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2657 } 2658 size--; 2659 } 2660 setup->sm_passkey_bit = offset; 2661 return 0; 2662 } 2663 #endif 2664 2665 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2666 static void sm_handle_random_result(uint8_t * data){ 2667 2668 #ifdef USE_MBEDTLS_FOR_ECDH 2669 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2670 int num_bytes = setup->sm_passkey_bit; 2671 if (num_bytes < 32){ 2672 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2673 } else { 2674 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2675 } 2676 num_bytes += 8; 2677 setup->sm_passkey_bit = num_bytes; 2678 2679 if (num_bytes >= 64){ 2680 // generate EC key 2681 setup->sm_passkey_bit = 0; 2682 mbedtls_mpi d; 2683 mbedtls_ecp_point P; 2684 mbedtls_mpi_init(&d); 2685 mbedtls_ecp_point_init(&P); 2686 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2687 log_info("gen keypair %x", res); 2688 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2689 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2690 mbedtls_mpi_write_binary(&d, ec_d, 32); 2691 mbedtls_ecp_point_free(&P); 2692 mbedtls_mpi_free(&d); 2693 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2694 sm_log_ec_keypair(); 2695 2696 #if 0 2697 printf("test dhkey check\n"); 2698 sm_key256_t dhkey; 2699 memcpy(setup->sm_peer_qx, ec_qx, 32); 2700 memcpy(setup->sm_peer_qy, ec_qy, 32); 2701 sm_sc_calculate_dhkey(dhkey); 2702 #endif 2703 2704 } 2705 } 2706 #endif 2707 2708 switch (rau_state){ 2709 case RAU_W4_RANDOM: 2710 // non-resolvable vs. resolvable 2711 switch (gap_random_adress_type){ 2712 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2713 // resolvable: use random as prand and calc address hash 2714 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2715 memcpy(sm_random_address, data, 3); 2716 sm_random_address[0] &= 0x3f; 2717 sm_random_address[0] |= 0x40; 2718 rau_state = RAU_GET_ENC; 2719 break; 2720 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2721 default: 2722 // "The two most significant bits of the address shall be equal to ‘0’"" 2723 memcpy(sm_random_address, data, 6); 2724 sm_random_address[0] &= 0x3f; 2725 rau_state = RAU_SET_ADDRESS; 2726 break; 2727 } 2728 return; 2729 default: 2730 break; 2731 } 2732 2733 // retrieve sm_connection provided to sm_random_start 2734 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2735 if (!connection) return; 2736 switch (connection->sm_engine_state){ 2737 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2738 case SM_SC_W4_GET_RANDOM_A: 2739 memcpy(&setup->sm_local_nonce[0], data, 8); 2740 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2741 break; 2742 case SM_SC_W4_GET_RANDOM_B: 2743 memcpy(&setup->sm_local_nonce[8], data, 8); 2744 // initiator & jw/nc -> send pairing random 2745 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2746 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2747 break; 2748 } else { 2749 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2750 } 2751 break; 2752 #endif 2753 2754 case SM_PH2_W4_RANDOM_TK: 2755 { 2756 // map random to 0-999999 without speding much cycles on a modulus operation 2757 uint32_t tk = little_endian_read_32(data,0); 2758 tk = tk & 0xfffff; // 1048575 2759 if (tk >= 999999){ 2760 tk = tk - 999999; 2761 } 2762 sm_reset_tk(); 2763 big_endian_store_32(setup->sm_tk, 12, tk); 2764 if (connection->sm_role){ 2765 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2766 } else { 2767 if (setup->sm_use_secure_connections){ 2768 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2769 } else { 2770 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2771 sm_trigger_user_response(connection); 2772 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2773 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2774 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2775 } 2776 } 2777 } 2778 return; 2779 } 2780 case SM_PH2_C1_W4_RANDOM_A: 2781 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2782 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2783 return; 2784 case SM_PH2_C1_W4_RANDOM_B: 2785 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2786 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2787 return; 2788 case SM_PH3_W4_RANDOM: 2789 reverse_64(data, setup->sm_local_rand); 2790 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2791 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2792 // no db for authenticated flag hack: store flag in bit 4 of LSB 2793 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2794 connection->sm_engine_state = SM_PH3_GET_DIV; 2795 return; 2796 case SM_PH3_W4_DIV: 2797 // use 16 bit from random value as div 2798 setup->sm_local_div = big_endian_read_16(data, 0); 2799 log_info_hex16("div", setup->sm_local_div); 2800 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2801 return; 2802 default: 2803 break; 2804 } 2805 } 2806 2807 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2808 2809 sm_connection_t * sm_conn; 2810 hci_con_handle_t con_handle; 2811 2812 switch (packet_type) { 2813 2814 case HCI_EVENT_PACKET: 2815 switch (hci_event_packet_get_type(packet)) { 2816 2817 case BTSTACK_EVENT_STATE: 2818 // bt stack activated, get started 2819 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2820 log_info("HCI Working!"); 2821 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2822 rau_state = RAU_IDLE; 2823 #ifdef USE_MBEDTLS_FOR_ECDH 2824 if (!sm_have_ec_keypair){ 2825 setup->sm_passkey_bit = 0; 2826 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2827 } 2828 #endif 2829 sm_run(); 2830 } 2831 break; 2832 2833 case HCI_EVENT_LE_META: 2834 switch (packet[2]) { 2835 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2836 2837 log_info("sm: connected"); 2838 2839 if (packet[3]) return; // connection failed 2840 2841 con_handle = little_endian_read_16(packet, 4); 2842 sm_conn = sm_get_connection_for_handle(con_handle); 2843 if (!sm_conn) break; 2844 2845 sm_conn->sm_handle = con_handle; 2846 sm_conn->sm_role = packet[6]; 2847 sm_conn->sm_peer_addr_type = packet[7]; 2848 reverse_bd_addr(&packet[8], 2849 sm_conn->sm_peer_address); 2850 2851 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2852 2853 // reset security properties 2854 sm_conn->sm_connection_encrypted = 0; 2855 sm_conn->sm_connection_authenticated = 0; 2856 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2857 sm_conn->sm_le_db_index = -1; 2858 2859 // prepare CSRK lookup (does not involve setup) 2860 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2861 2862 // just connected -> everything else happens in sm_run() 2863 if (sm_conn->sm_role){ 2864 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2865 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2866 if (sm_slave_request_security) { 2867 // request security if requested by app 2868 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2869 } else { 2870 // otherwise, wait for pairing request 2871 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2872 } 2873 } 2874 break; 2875 } else { 2876 // master 2877 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2878 } 2879 break; 2880 2881 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2882 con_handle = little_endian_read_16(packet, 3); 2883 sm_conn = sm_get_connection_for_handle(con_handle); 2884 if (!sm_conn) break; 2885 2886 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2887 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2888 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2889 break; 2890 } 2891 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2892 // PH2 SEND LTK as we need to exchange keys in PH3 2893 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2894 break; 2895 } 2896 2897 // store rand and ediv 2898 reverse_64(&packet[5], sm_conn->sm_local_rand); 2899 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2900 2901 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 2902 // potentially stored LTK is from the master 2903 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 2904 sm_start_calculating_ltk_from_ediv_and_rand(sm_conn); 2905 break; 2906 } 2907 2908 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2909 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2910 #else 2911 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 2912 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2913 #endif 2914 break; 2915 2916 default: 2917 break; 2918 } 2919 break; 2920 2921 case HCI_EVENT_ENCRYPTION_CHANGE: 2922 con_handle = little_endian_read_16(packet, 3); 2923 sm_conn = sm_get_connection_for_handle(con_handle); 2924 if (!sm_conn) break; 2925 2926 sm_conn->sm_connection_encrypted = packet[5]; 2927 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2928 sm_conn->sm_actual_encryption_key_size); 2929 log_info("event handler, state %u", sm_conn->sm_engine_state); 2930 if (!sm_conn->sm_connection_encrypted) break; 2931 // continue if part of initial pairing 2932 switch (sm_conn->sm_engine_state){ 2933 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2934 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2935 sm_done_for_handle(sm_conn->sm_handle); 2936 break; 2937 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2938 if (sm_conn->sm_role){ 2939 // slave 2940 if (setup->sm_use_secure_connections){ 2941 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2942 } else { 2943 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2944 } 2945 } else { 2946 // master 2947 if (sm_key_distribution_all_received(sm_conn)){ 2948 // skip receiving keys as there are none 2949 sm_key_distribution_handle_all_received(sm_conn); 2950 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2951 } else { 2952 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2953 } 2954 } 2955 break; 2956 default: 2957 break; 2958 } 2959 break; 2960 2961 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2962 con_handle = little_endian_read_16(packet, 3); 2963 sm_conn = sm_get_connection_for_handle(con_handle); 2964 if (!sm_conn) break; 2965 2966 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2967 log_info("event handler, state %u", sm_conn->sm_engine_state); 2968 // continue if part of initial pairing 2969 switch (sm_conn->sm_engine_state){ 2970 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2971 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2972 sm_done_for_handle(sm_conn->sm_handle); 2973 break; 2974 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2975 if (sm_conn->sm_role){ 2976 // slave 2977 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2978 } else { 2979 // master 2980 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2981 } 2982 break; 2983 default: 2984 break; 2985 } 2986 break; 2987 2988 2989 case HCI_EVENT_DISCONNECTION_COMPLETE: 2990 con_handle = little_endian_read_16(packet, 3); 2991 sm_done_for_handle(con_handle); 2992 sm_conn = sm_get_connection_for_handle(con_handle); 2993 if (!sm_conn) break; 2994 2995 // delete stored bonding on disconnect with authentication failure in ph0 2996 if (sm_conn->sm_role == 0 2997 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2998 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2999 le_device_db_remove(sm_conn->sm_le_db_index); 3000 } 3001 3002 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3003 sm_conn->sm_handle = 0; 3004 break; 3005 3006 case HCI_EVENT_COMMAND_COMPLETE: 3007 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3008 sm_handle_encryption_result(&packet[6]); 3009 break; 3010 } 3011 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3012 sm_handle_random_result(&packet[6]); 3013 break; 3014 } 3015 break; 3016 default: 3017 break; 3018 } 3019 break; 3020 default: 3021 break; 3022 } 3023 3024 sm_run(); 3025 } 3026 3027 static inline int sm_calc_actual_encryption_key_size(int other){ 3028 if (other < sm_min_encryption_key_size) return 0; 3029 if (other < sm_max_encryption_key_size) return other; 3030 return sm_max_encryption_key_size; 3031 } 3032 3033 3034 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3035 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3036 switch (method){ 3037 case JUST_WORKS: 3038 case NK_BOTH_INPUT: 3039 return 1; 3040 default: 3041 return 0; 3042 } 3043 } 3044 // responder 3045 3046 static int sm_passkey_used(stk_generation_method_t method){ 3047 switch (method){ 3048 case PK_RESP_INPUT: 3049 return 1; 3050 default: 3051 return 0; 3052 } 3053 } 3054 #endif 3055 3056 /** 3057 * @return ok 3058 */ 3059 static int sm_validate_stk_generation_method(void){ 3060 // check if STK generation method is acceptable by client 3061 switch (setup->sm_stk_generation_method){ 3062 case JUST_WORKS: 3063 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3064 case PK_RESP_INPUT: 3065 case PK_INIT_INPUT: 3066 case OK_BOTH_INPUT: 3067 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3068 case OOB: 3069 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3070 case NK_BOTH_INPUT: 3071 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3072 return 1; 3073 default: 3074 return 0; 3075 } 3076 } 3077 3078 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3079 3080 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3081 sm_run(); 3082 } 3083 3084 if (packet_type != SM_DATA_PACKET) return; 3085 3086 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3087 if (!sm_conn) return; 3088 3089 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3090 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3091 return; 3092 } 3093 3094 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3095 3096 int err; 3097 3098 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3099 uint8_t buffer[5]; 3100 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3101 buffer[1] = 3; 3102 little_endian_store_16(buffer, 2, con_handle); 3103 buffer[4] = packet[1]; 3104 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3105 return; 3106 } 3107 3108 switch (sm_conn->sm_engine_state){ 3109 3110 // a sm timeout requries a new physical connection 3111 case SM_GENERAL_TIMEOUT: 3112 return; 3113 3114 // Initiator 3115 case SM_INITIATOR_CONNECTED: 3116 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3117 sm_pdu_received_in_wrong_state(sm_conn); 3118 break; 3119 } 3120 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3121 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3122 break; 3123 } 3124 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3125 sm_key_t ltk; 3126 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3127 if (!sm_is_null_key(ltk)){ 3128 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3129 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3130 } else { 3131 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3132 } 3133 break; 3134 } 3135 // otherwise, store security request 3136 sm_conn->sm_security_request_received = 1; 3137 break; 3138 3139 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3140 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3141 sm_pdu_received_in_wrong_state(sm_conn); 3142 break; 3143 } 3144 // store pairing request 3145 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3146 err = sm_stk_generation_init(sm_conn); 3147 if (err){ 3148 setup->sm_pairing_failed_reason = err; 3149 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3150 break; 3151 } 3152 3153 // generate random number first, if we need to show passkey 3154 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3155 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3156 break; 3157 } 3158 3159 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3160 if (setup->sm_use_secure_connections){ 3161 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3162 if (setup->sm_stk_generation_method == JUST_WORKS){ 3163 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3164 sm_trigger_user_response(sm_conn); 3165 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3166 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3167 } 3168 } else { 3169 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3170 } 3171 break; 3172 } 3173 #endif 3174 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3175 sm_trigger_user_response(sm_conn); 3176 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3177 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3178 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3179 } 3180 break; 3181 3182 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3183 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3184 sm_pdu_received_in_wrong_state(sm_conn); 3185 break; 3186 } 3187 3188 // store s_confirm 3189 reverse_128(&packet[1], setup->sm_peer_confirm); 3190 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3191 break; 3192 3193 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3194 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3195 sm_pdu_received_in_wrong_state(sm_conn); 3196 break;; 3197 } 3198 3199 // received random value 3200 reverse_128(&packet[1], setup->sm_peer_random); 3201 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3202 break; 3203 3204 // Responder 3205 case SM_RESPONDER_IDLE: 3206 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3207 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3208 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3209 sm_pdu_received_in_wrong_state(sm_conn); 3210 break;; 3211 } 3212 3213 // store pairing request 3214 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3215 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3216 break; 3217 3218 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3219 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3220 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3221 sm_pdu_received_in_wrong_state(sm_conn); 3222 break; 3223 } 3224 3225 // store public key for DH Key calculation 3226 reverse_256(&packet[01], setup->sm_peer_qx); 3227 reverse_256(&packet[33], setup->sm_peer_qy); 3228 3229 #ifdef USE_MBEDTLS_FOR_ECDH 3230 // validate public key 3231 mbedtls_ecp_point Q; 3232 mbedtls_ecp_point_init( &Q ); 3233 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3234 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3235 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 3236 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3237 mbedtls_ecp_point_free( & Q); 3238 if (err){ 3239 log_error("sm: peer public key invalid %x", err); 3240 // uses "unspecified reason", there is no "public key invalid" error code 3241 sm_pdu_received_in_wrong_state(sm_conn); 3242 break; 3243 } 3244 3245 #endif 3246 if (sm_conn->sm_role){ 3247 // responder 3248 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3249 } else { 3250 // initiator 3251 // stk generation method 3252 // passkey entry: notify app to show passkey or to request passkey 3253 switch (setup->sm_stk_generation_method){ 3254 case JUST_WORKS: 3255 case NK_BOTH_INPUT: 3256 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3257 break; 3258 case PK_RESP_INPUT: 3259 sm_sc_start_calculating_local_confirm(sm_conn); 3260 break; 3261 case PK_INIT_INPUT: 3262 case OK_BOTH_INPUT: 3263 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3264 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3265 break; 3266 } 3267 sm_sc_start_calculating_local_confirm(sm_conn); 3268 break; 3269 case OOB: 3270 // TODO: implement SC OOB 3271 break; 3272 } 3273 } 3274 break; 3275 3276 case SM_SC_W4_CONFIRMATION: 3277 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3278 sm_pdu_received_in_wrong_state(sm_conn); 3279 break; 3280 } 3281 // received confirm value 3282 reverse_128(&packet[1], setup->sm_peer_confirm); 3283 3284 if (sm_conn->sm_role){ 3285 // responder 3286 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3287 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3288 // still waiting for passkey 3289 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3290 break; 3291 } 3292 } 3293 sm_sc_start_calculating_local_confirm(sm_conn); 3294 } else { 3295 // initiator 3296 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3297 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3298 } else { 3299 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3300 } 3301 } 3302 break; 3303 3304 case SM_SC_W4_PAIRING_RANDOM: 3305 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3306 sm_pdu_received_in_wrong_state(sm_conn); 3307 break; 3308 } 3309 3310 // received random value 3311 reverse_128(&packet[1], setup->sm_peer_nonce); 3312 3313 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3314 // only check for JUST WORK/NC in initiator role AND passkey entry 3315 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3316 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3317 } 3318 3319 sm_sc_state_after_receiving_random(sm_conn); 3320 break; 3321 3322 case SM_SC_W2_CALCULATE_G2: 3323 case SM_SC_W4_CALCULATE_G2: 3324 case SM_SC_W2_CALCULATE_F5_SALT: 3325 case SM_SC_W4_CALCULATE_F5_SALT: 3326 case SM_SC_W2_CALCULATE_F5_MACKEY: 3327 case SM_SC_W4_CALCULATE_F5_MACKEY: 3328 case SM_SC_W2_CALCULATE_F5_LTK: 3329 case SM_SC_W4_CALCULATE_F5_LTK: 3330 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3331 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3332 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3333 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3334 sm_pdu_received_in_wrong_state(sm_conn); 3335 break; 3336 } 3337 // store DHKey Check 3338 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3339 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3340 3341 // have we been only waiting for dhkey check command? 3342 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3343 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3344 } 3345 break; 3346 #endif 3347 3348 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3349 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3350 sm_pdu_received_in_wrong_state(sm_conn); 3351 break; 3352 } 3353 3354 // received confirm value 3355 reverse_128(&packet[1], setup->sm_peer_confirm); 3356 3357 // notify client to hide shown passkey 3358 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3359 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3360 } 3361 3362 // handle user cancel pairing? 3363 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3364 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3365 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3366 break; 3367 } 3368 3369 // wait for user action? 3370 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3371 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3372 break; 3373 } 3374 3375 // calculate and send local_confirm 3376 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3377 break; 3378 3379 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3380 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3381 sm_pdu_received_in_wrong_state(sm_conn); 3382 break;; 3383 } 3384 3385 // received random value 3386 reverse_128(&packet[1], setup->sm_peer_random); 3387 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3388 break; 3389 3390 case SM_PH3_RECEIVE_KEYS: 3391 switch(packet[0]){ 3392 case SM_CODE_ENCRYPTION_INFORMATION: 3393 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3394 reverse_128(&packet[1], setup->sm_peer_ltk); 3395 break; 3396 3397 case SM_CODE_MASTER_IDENTIFICATION: 3398 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3399 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3400 reverse_64(&packet[3], setup->sm_peer_rand); 3401 break; 3402 3403 case SM_CODE_IDENTITY_INFORMATION: 3404 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3405 reverse_128(&packet[1], setup->sm_peer_irk); 3406 break; 3407 3408 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3409 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3410 setup->sm_peer_addr_type = packet[1]; 3411 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3412 break; 3413 3414 case SM_CODE_SIGNING_INFORMATION: 3415 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3416 reverse_128(&packet[1], setup->sm_peer_csrk); 3417 break; 3418 default: 3419 // Unexpected PDU 3420 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3421 break; 3422 } 3423 // done with key distribution? 3424 if (sm_key_distribution_all_received(sm_conn)){ 3425 3426 sm_key_distribution_handle_all_received(sm_conn); 3427 3428 if (sm_conn->sm_role){ 3429 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3430 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3431 } else { 3432 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3433 sm_done_for_handle(sm_conn->sm_handle); 3434 } 3435 } else { 3436 if (setup->sm_use_secure_connections){ 3437 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3438 } else { 3439 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3440 } 3441 } 3442 } 3443 break; 3444 default: 3445 // Unexpected PDU 3446 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3447 break; 3448 } 3449 3450 // try to send preparared packet 3451 sm_run(); 3452 } 3453 3454 // Security Manager Client API 3455 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3456 sm_get_oob_data = get_oob_data_callback; 3457 } 3458 3459 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3460 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3461 } 3462 3463 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3464 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3465 } 3466 3467 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3468 sm_min_encryption_key_size = min_size; 3469 sm_max_encryption_key_size = max_size; 3470 } 3471 3472 void sm_set_authentication_requirements(uint8_t auth_req){ 3473 sm_auth_req = auth_req; 3474 } 3475 3476 void sm_set_io_capabilities(io_capability_t io_capability){ 3477 sm_io_capabilities = io_capability; 3478 } 3479 3480 void sm_set_request_security(int enable){ 3481 sm_slave_request_security = enable; 3482 } 3483 3484 void sm_set_er(sm_key_t er){ 3485 memcpy(sm_persistent_er, er, 16); 3486 } 3487 3488 void sm_set_ir(sm_key_t ir){ 3489 memcpy(sm_persistent_ir, ir, 16); 3490 } 3491 3492 // Testing support only 3493 void sm_test_set_irk(sm_key_t irk){ 3494 memcpy(sm_persistent_irk, irk, 16); 3495 sm_persistent_irk_ready = 1; 3496 } 3497 3498 void sm_test_use_fixed_local_csrk(void){ 3499 test_use_fixed_local_csrk = 1; 3500 } 3501 3502 void sm_init(void){ 3503 // set some (BTstack default) ER and IR 3504 int i; 3505 sm_key_t er; 3506 sm_key_t ir; 3507 for (i=0;i<16;i++){ 3508 er[i] = 0x30 + i; 3509 ir[i] = 0x90 + i; 3510 } 3511 sm_set_er(er); 3512 sm_set_ir(ir); 3513 // defaults 3514 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3515 | SM_STK_GENERATION_METHOD_OOB 3516 | SM_STK_GENERATION_METHOD_PASSKEY 3517 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3518 3519 sm_max_encryption_key_size = 16; 3520 sm_min_encryption_key_size = 7; 3521 3522 sm_cmac_state = CMAC_IDLE; 3523 dkg_state = DKG_W4_WORKING; 3524 rau_state = RAU_W4_WORKING; 3525 sm_aes128_state = SM_AES128_IDLE; 3526 sm_address_resolution_test = -1; // no private address to resolve yet 3527 sm_address_resolution_ah_calculation_active = 0; 3528 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3529 sm_address_resolution_general_queue = NULL; 3530 3531 gap_random_adress_update_period = 15 * 60 * 1000L; 3532 3533 sm_active_connection = 0; 3534 3535 test_use_fixed_local_csrk = 0; 3536 3537 // register for HCI Events from HCI 3538 hci_event_callback_registration.callback = &sm_event_packet_handler; 3539 hci_add_event_handler(&hci_event_callback_registration); 3540 3541 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3542 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3543 3544 #ifdef USE_MBEDTLS_FOR_ECDH 3545 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3546 3547 #ifndef HAVE_MALLOC 3548 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3549 #endif 3550 mbedtls_ecp_group_init(&mbedtls_ec_group); 3551 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3552 3553 #if 0 3554 // test 3555 sm_test_use_fixed_ec_keypair(); 3556 if (sm_have_ec_keypair){ 3557 printf("test dhkey check\n"); 3558 sm_key256_t dhkey; 3559 memcpy(setup->sm_peer_qx, ec_qx, 32); 3560 memcpy(setup->sm_peer_qy, ec_qy, 32); 3561 sm_sc_calculate_dhkey(dhkey); 3562 } 3563 #endif 3564 #endif 3565 } 3566 3567 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3568 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3569 memcpy(ec_qx, qx, 32); 3570 memcpy(ec_qy, qy, 32); 3571 memcpy(ec_d, d, 32); 3572 sm_have_ec_keypair = 1; 3573 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3574 #endif 3575 } 3576 3577 void sm_test_use_fixed_ec_keypair(void){ 3578 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3579 #ifdef USE_MBEDTLS_FOR_ECDH 3580 // use test keypair from spec 3581 mbedtls_mpi x; 3582 mbedtls_mpi_init(&x); 3583 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3584 mbedtls_mpi_write_binary(&x, ec_d, 32); 3585 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3586 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3587 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3588 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3589 mbedtls_mpi_free(&x); 3590 #endif 3591 sm_have_ec_keypair = 1; 3592 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3593 #endif 3594 } 3595 3596 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3597 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3598 if (!hci_con) return NULL; 3599 return &hci_con->sm_connection; 3600 } 3601 3602 // @returns 0 if not encrypted, 7-16 otherwise 3603 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3604 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3605 if (!sm_conn) return 0; // wrong connection 3606 if (!sm_conn->sm_connection_encrypted) return 0; 3607 return sm_conn->sm_actual_encryption_key_size; 3608 } 3609 3610 int sm_authenticated(hci_con_handle_t con_handle){ 3611 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3612 if (!sm_conn) return 0; // wrong connection 3613 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3614 return sm_conn->sm_connection_authenticated; 3615 } 3616 3617 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3618 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3619 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3620 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3621 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3622 return sm_conn->sm_connection_authorization_state; 3623 } 3624 3625 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3626 switch (sm_conn->sm_engine_state){ 3627 case SM_GENERAL_IDLE: 3628 case SM_RESPONDER_IDLE: 3629 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3630 sm_run(); 3631 break; 3632 default: 3633 break; 3634 } 3635 } 3636 3637 /** 3638 * @brief Trigger Security Request 3639 */ 3640 void sm_send_security_request(hci_con_handle_t con_handle){ 3641 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3642 if (!sm_conn) return; 3643 sm_send_security_request_for_connection(sm_conn); 3644 } 3645 3646 // request pairing 3647 void sm_request_pairing(hci_con_handle_t con_handle){ 3648 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3649 if (!sm_conn) return; // wrong connection 3650 3651 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3652 if (sm_conn->sm_role){ 3653 sm_send_security_request_for_connection(sm_conn); 3654 } else { 3655 // used as a trigger to start central/master/initiator security procedures 3656 uint16_t ediv; 3657 sm_key_t ltk; 3658 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3659 switch (sm_conn->sm_irk_lookup_state){ 3660 case IRK_LOOKUP_FAILED: 3661 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3662 break; 3663 case IRK_LOOKUP_SUCCEEDED: 3664 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3665 if (!sm_is_null_key(ltk) || ediv){ 3666 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3667 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3668 } else { 3669 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3670 } 3671 break; 3672 default: 3673 sm_conn->sm_bonding_requested = 1; 3674 break; 3675 } 3676 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3677 sm_conn->sm_bonding_requested = 1; 3678 } 3679 } 3680 sm_run(); 3681 } 3682 3683 // called by client app on authorization request 3684 void sm_authorization_decline(hci_con_handle_t con_handle){ 3685 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3686 if (!sm_conn) return; // wrong connection 3687 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3688 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3689 } 3690 3691 void sm_authorization_grant(hci_con_handle_t con_handle){ 3692 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3693 if (!sm_conn) return; // wrong connection 3694 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3695 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3696 } 3697 3698 // GAP Bonding API 3699 3700 void sm_bonding_decline(hci_con_handle_t con_handle){ 3701 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3702 if (!sm_conn) return; // wrong connection 3703 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3704 3705 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3706 switch (setup->sm_stk_generation_method){ 3707 case PK_RESP_INPUT: 3708 case PK_INIT_INPUT: 3709 case OK_BOTH_INPUT: 3710 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3711 break; 3712 case NK_BOTH_INPUT: 3713 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3714 break; 3715 case JUST_WORKS: 3716 case OOB: 3717 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3718 break; 3719 } 3720 } 3721 sm_run(); 3722 } 3723 3724 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3725 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3726 if (!sm_conn) return; // wrong connection 3727 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3728 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3729 if (setup->sm_use_secure_connections){ 3730 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3731 } else { 3732 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3733 } 3734 } 3735 3736 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3737 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3738 sm_sc_prepare_dhkey_check(sm_conn); 3739 } 3740 #endif 3741 3742 sm_run(); 3743 } 3744 3745 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3746 // for now, it's the same 3747 sm_just_works_confirm(con_handle); 3748 } 3749 3750 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3751 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3752 if (!sm_conn) return; // wrong connection 3753 sm_reset_tk(); 3754 big_endian_store_32(setup->sm_tk, 12, passkey); 3755 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3756 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3757 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3758 } 3759 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3760 memcpy(setup->sm_ra, setup->sm_tk, 16); 3761 memcpy(setup->sm_rb, setup->sm_tk, 16); 3762 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3763 sm_sc_start_calculating_local_confirm(sm_conn); 3764 } 3765 #endif 3766 sm_run(); 3767 } 3768 3769 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3770 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3771 if (!sm_conn) return; // wrong connection 3772 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3773 setup->sm_keypress_notification = action; 3774 sm_run(); 3775 } 3776 3777 /** 3778 * @brief Identify device in LE Device DB 3779 * @param handle 3780 * @returns index from le_device_db or -1 if not found/identified 3781 */ 3782 int sm_le_device_index(hci_con_handle_t con_handle ){ 3783 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3784 if (!sm_conn) return -1; 3785 return sm_conn->sm_le_db_index; 3786 } 3787 3788 // GAP LE API 3789 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3790 gap_random_address_update_stop(); 3791 gap_random_adress_type = random_address_type; 3792 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3793 gap_random_address_update_start(); 3794 gap_random_address_trigger(); 3795 } 3796 3797 gap_random_address_type_t gap_random_address_get_mode(void){ 3798 return gap_random_adress_type; 3799 } 3800 3801 void gap_random_address_set_update_period(int period_ms){ 3802 gap_random_adress_update_period = period_ms; 3803 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3804 gap_random_address_update_stop(); 3805 gap_random_address_update_start(); 3806 } 3807 3808 void gap_random_address_set(bd_addr_t addr){ 3809 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3810 memcpy(sm_random_address, addr, 6); 3811 rau_state = RAU_SET_ADDRESS; 3812 sm_run(); 3813 } 3814 3815 /* 3816 * @brief Set Advertisement Paramters 3817 * @param adv_int_min 3818 * @param adv_int_max 3819 * @param adv_type 3820 * @param direct_address_type 3821 * @param direct_address 3822 * @param channel_map 3823 * @param filter_policy 3824 * 3825 * @note own_address_type is used from gap_random_address_set_mode 3826 */ 3827 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3828 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3829 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3830 direct_address_typ, direct_address, channel_map, filter_policy); 3831 } 3832 3833